There are four primary types of drug tests: urine, hair, blood and saliva. Most common is the urine test which has the benefit of being inexpensive and less intrusive than the blood test.
Urine Drug Tests
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Are the least expensive of the test methods ($7 to $50 for a home version).
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Can be done at home (for example by parents or to test ones self)
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Detect use primarily within the past few weeks (sometimes longer with regular use).
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Can be affected by abstaining from use for a period of time before the test.
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Are often temperature, PH and/or creatinine testing to insure sample integrity.
A urine drug test requires that one provide a sample of urine. Either a dip test card is used on site for immediate results or the sample is sent away to a lab to undergo analysis. The majority of tests administered in pre-hire and random testing are the "at home" dip variety. Most "commercial" dip variety type tests have higher thresholds for a positive than do the standard dip tests. If a positive result (drug presence indicated) is found, the sample is usually sent to a lab for confirmation. This is largely due to the costliness of laboratory testing and time it takes to process and receive results.
Hair Drug Tests
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Are currently several times more expensive than urine tests ( $100 to $150).
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Detect substance use over a much longer period
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Do not usually detect use within the past week.
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Require a sample of hair about the diameter of a pencil and 1.5 inches long. They can not be done with a single hair.
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Test positive a little more than twice as often as a urine test.
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Are not significantly affected by brief periods of abstinence from drugs.
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Can sometimes be used to determine when use occurred and if it has been discontinued.
Hair testing is considered very accurate and testing often is looking for use within the last 90 days. As hair grows out any drugs used are encased in the hair shaft. The longer the hair, the longer back in time the individual's drug history can potentially be detected. Human Hair grows an average of .5 inches/month, which corresponds to 30 days of possible drug testing for every .5 inch and a 1.5 inches sample is typically taken for a test of around 90 days of drug use. Some people attempt to circumvent this through shaving their heads. This does not usually work as hair from the underarms, arms, legs, and even pubic hair can be used.
Blood Drug Tests
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Are the most expensive method of testing.
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Are considered the most intrusive method of testing.
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Are the most accurate method of testing.
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Are the least common method of testing (most likely due to cost).
Blood drug tests are not commonly performed as they are expensive, require expensive on site personnel to draw the blood, are expensive to process and typically do not provide any historical usage information. Unlike urine drug tests, blood drug tests measure the actual substance in your system, not the metabolites your body produces when substances are ingested. Blood drug tests are frequently used by agencies or companies to determine if someone was under the influence of some substance leading to an accident or event. Health insurance companies also perform blood drug tests before giving out a policy looking mostly for marijuana, nicotine and/or cocaine usage.
Saliva Drug Tests
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Are a little more expensive than urine testing, but less than hair or blood. ($15 to $75).
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Are becoming more common.
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Are easy to administer but require lab processing to ensure accuracy.
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Detect use primarily within the past few days to weeks.
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Can detect more recent use than other testing methods.
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Have no nationally accepted standards or cutoff concentrations for detection, making results greatly dependent on the specific product purchased. This could also make results less-reliable and/or acceptable for legal cases.
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More reliable for detection of Methamphetamine and Opiates, less reliable for THC or Cannabinoids.
Saliva drug tests can generally detect use during the previous few days. On-site saliva based tests enable the implementation of random testing programs, proven to be the most effective type of drug screening and are as accurate as urine drug tests. Saliva Drug testing is usually performed by employers for either pre-employment, random, post-accident, reasonable suspicion, or return-to-duty drug testing. Saliva based testing most closely mimics results found with blood and is preferable for detecting on-the-job drug use or in post-accident applications in this case because the degree of intoxication can be approximated based on the amount of substance.
